Improvement in the generation of adsorption isotherm data in the elution by characteristic points method—The ECP-slope approach

Determination of adsorption isotherms in supercritical fluid chromatography

“…A systematic error can be caused by the selection of the integration starting point at concentration equal to 0 and this error was reduced in a recent study by replacing the classical integration with the use of raw slope data [24]. This approach allows excluding extreme low concentration data, which are more affected by the separation systems limited efficiency.…”

“…The Elution by Characteristic Points (ECP) method generates adsorption isotherm data from the diffuse part(s) of an elution profile [4,23,24] and the theory is derived using the ideal model that assumes infinite column efficiency. However, the efficiency of a real column is finite [4] and this will lead to some error in the adsorption isotherm determination but this error decreases with increasing column efficiency [25,26].…”

Peak deformations in preparative supercritical fluid chromatography due to co-solvent adsorption

“…One of the fastest methods for determine the adsorption isotherm is the elution by characteristic point (ECP) method [29,34], in which the raw adsorption isotherm data is determined from the diffuse part of an overloaded elution profile [29]. In the present study the slope version of the ECP method is instead used [35,36]. For a type I adsorption isotherm (convex, e.g.…”

A closer study of peak distortions in supercritical fluid chromatography as generated by the injection

“…The adsorption isotherms of antipyrine were determined using the elution by characteristic method in slope mode [39]. Using the ECP method it is necessary to have a calibration curve to convert detector response (R) to concentration (C), this was done by fitting the detector response for three different column loads for each condition to Eq.…”